People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

Man With Knife Sticking Out Of His Back Horrifies McDonald's Patrons In New York City; Now Hospitalized In Serious Condition

Customers at a McDonald’s in Jamaica, Queens didn’t know what to make of a man who strolled into the fast food restaurant this past Tuesday with a knife sticking out of his back and blood running down the back of his shirt. According to witnesses, Andrew Hardy suffered his life-threatening wound after being involved in a confrontation with two other men.

“I heard everybody screaming and it was a lot of commotion,” witness Tromaine Yancey told CBS News. “The guy came and he was standing there with a knife in his back, and it was a kitchen knife. He was on the phone. I’m pretty sure he was on the phone talking to somebody in his family or a loved one or something. He was talking to them and telling them it might be the last time he’s speaking to them.”

Police investigating the incident said a group of men were seen fighting on a street corner moments before Hardy entered the McDonald’s. Authorities are now looking to question two men who may have been involved in the scuffle with the victim. The 53-year-old man was taken to nearby Jamaica Hospital Medical Center in Queens, where he was later released. Hardy told reporters that he was “blessed to be alive.”

“The next thing we know, there [Hardy] goes, telling me he’s got a knife in his back,” Hardy’s friend, Michel Green told The New York Post. “He came to me. He said, ‘Mike, man, I was stabbed in the back, man.’ He was scared, he was shaking. He was cool and calm. But you could tell he was shaken up. I went to pull the knife out, but someone said, ‘No, no! It might have hit an artery!’”